Er:YAG激光对树脂粘结牙釉质强度的影响

Effect of Er:YAG laser on shear strength of enamel surface

目的探讨Er:YAG激光处理釉质表面对树脂粘结牙釉质剪切强度的影响。方法选取40颗完整的人离体双尖牙,在颊面用金刚砂片切出略大于4mm×4mm的平面,分为4组,每组10颗牙。分别对牙釉质表面进行处理,A组:酸蚀(35%磷酸),B组:Er:YAG激光,C组:Er:YAG激光加酸蚀,D组:酸蚀加Er:YAG激光;每组8颗牙分别在处理后的牙釉质表面粘结光固化复合树脂,进行剪切强度测试,2颗牙扫描电镜观察。结果 C组的剪切强度值最高(16.0±4.2Mp),与其它组有显著性差异(P<0.05);D组的剪切强度值最低(7.1±2.9Mpa),与其它组有显著性差异(P<0.05);A组与B组的剪切强度值为11.3±5.7Mpa和10.3±4.6Mpa,二者相比差异无显著性(P>0.05)。扫描电镜观察A组:表面较平整,空洞、裂隙小而均匀;B组:表面凹凸不平,结构紊乱,有大小不一的坑洞及少量碎屑,未见熔融现象;C组:表面不平整,整体结构均匀,无明显碎屑及裂隙,秞柱排列整齐;D组:孔隙不均匀,部分区域较为平整,可见较长的裂隙及碎屑。结论 Er:YAG激光蚀刻可达到类似酸蚀的效果。Er:YAG激光照射后再酸蚀可明显提高剪切强度。

Objective To investigate the etching effect of Er： YAG laser on shear strength of enamel surface. Methods Forty intact isolated human premolars were divided into four groups according to the different treatment methods： group A：acid etching （35% phosphoric acid） ,group B： Er： YAG laser, group C：acid etching after Er： YAG laser, group D： Er： YAG laser after acid etching. The enamel surface was treated, light-cured composite resin bonded and the shear strength tested. Two specimens in each group were prepared and observed by scanning electron microscope. Results The shear strength was the highest in group C （ P 〈 0. 05 ）, and the lowest in group D （ P 〈 0. 05 ） compared with other groups. There was no significant difference between group A and group B （ P 〉 0. 05 ）. Scanning electron microscope showed that, in group A, the enamel surface was smooth with micro-regularity craterlet and microcrack. In group B, the surface was rough with micro-irregularity craterlet, microcrack and scaly structure. In group C, the surface was not smooth with few micro-irregularity microcrack or flaky structure. In group D, the surface had microirregularity microcrack and longer microcrack. Conclusion Er： YAG laser etching can achieve similar effect as acid. Er： YAG laser irradiation before acid etchinz can imDreve the shear strength.